Fabrication of large structures which comprise multiple units bolted together by means of flange plates, such as booms, require precise alignment of the holes and mating surfaces at the interface of the units. Consequently, booms and other structural units are generally manufactured by employing a "jig" or "fixture" to ensure the proper spacing and alignment of the flange plates at the end of each unit as it is fabricated.
Alternatively, the units are fabricated and then machined after welding which also requires expensive equipment and may also require a large jig or fixture.
In some instances, it is necessary or highly desirable to build the structural unit in the field. One instance would be where the structural unit is so large that it could not be readily transported to the desired final location. Another instance may be where the structure is very large and dimensionally exceeds the capabilities of standard machine tools and machine shops. In this situation, the jig or fixture may even be too large to transport to the job site and likewise would be very expensive for use on a single project.
Therefore, a need has arisen in the industry for a method and apparatus for constructing structures consisting of multiple removable or interchangeable sections while maintaining a high degree of accuracy of construction.